Blackout bedroom blinds?

I got upholstery fabric with black sort of vinyl-like backing. No need to hem. Cut to size of window and we put command hooks up under the valance and I sewed cloth tabs on the square. But, now I see I can just cut a hole in the fabric and it will not ravel. You can also hem the bottom to fit a dowel rod in and then roll up part way and secure with a plastic toothy hair clip. You could also skip the command hooks (which I think I will do in next camper cause sometimes they come loose) and just cut the fabric larger and use quilters safety pins and pin it to the valance (leaving pin open). Will not damage valance fabric and after all, this is only done at night and so who sees it? No matter what it looks like, right. These fold up easily to store.